Traffic light post



1937.. H. GRUSSENDORF ET AL 2,094,741

TRAFFIC LIGHT POST Filed Nov. 1, 1934 Patented Oct. 5, 1937 UNITED STATES PATENT OFFICE TRAFFIC LIGHT POST Hanns Grussendorf and'Alexander Varren, Essen,

' Germany Application November 1, 1934, Serial No. 750,995 In Germany November 2, 1933 4 Claims.

The invention relates to a light post intended for the regulation of street traffic, and has particularly reference to a post providedwith lighting openings and 'an internal source of light.

general of a perforated cast iron shell in the perforations of which, that have comparatively large area, are mounted glass bodies which receive light from a series of lamps mounted behind them. In order to obtain .a sufiicient light effect with posts of this type, a large number of lamps of high candle power must be provided, and, consequently, ventilation openings also.. These openings, however, result in the inner parts of the post ture. Furthermore, if the sourceof light fails to act, the light post no longer fulfills its object as a trafiic signal but even becomes a danger for the traffic. I

' The object of the invention is to overcome all these drawbacks. The object is achieved according to the invention by the fact that the inner surface of the shell is covered with a reflecting material and provided with a plurality of small perforations distributed over the whole shell and arranged so as to form a light lattice work, that is, situated close side by side, that in these perforations are inserted small glass bodies which possess light interceptive portions projecting into the interior of the shell and which are capable both of intercepting and condensing the light rays coming from an internal central source of light and of totally reflecting light rays meeting them from outside.

The invention further comprises a form of refleeting body which is particularly adapted for internallyilluminated traific posts, and new means for the fixation of these bodies and, finally, a new constructional form of the post itself.

Some embodiments of the various novel features of the present invention are illustrated by way of example in the accompanying drawing, in which Figure l-is a side elevation, partly in vertical central section, of an embodiment of the new traffic post,

Figure 2 is a section on line II'II'of Figure 1,

Figure 3 is a central section of a conical reflecting body,

Figure 4 shows another form of reflector, in front'view, and 4 Figure 5 is a vertical section of thelower portion of a tramc post and shows a modified form of pedestal.

i In the embodiment illustrated in Figures 1 to 3 The known light posts of this type consist in very soon becoming dusty and injured by moisthe traffic post comprises a sheet metal shell I covered at the top by a cap 2 and mounted on a pedestal 4 wherein the illuminating-means are lodged. The pedestal is not directly screwed onto a base plate 6 that rests on a foundation 5, but 5 is loosely mounted on a conical projection 8 of the base plate .6 by means of a correspondingly shaped circular recess 1.

The angle of the cone of these parts is comparatively great and their height is so small that, when 10 a car runs against the post, the shell is capable of giving way and turning over without hindrance.

In order that the post may be capable of withstanding normal stresses, such as wind pressure, shocks or the pressure of a person leaning against it, it is secured in its vertical position by transverse bolts 29, split pins, screws or the like. These fastening means are so weak that they are sheared off when a car runs against the post, without the remaining parts thereof being injured worth mentioning. When such a post has been upset, it is only necessary to remove the sheared-on bolts 29 or the like, whereupon the post may be adjusted anew in vertical position on the conical projection 8 of the base plate and new bolts 5 applied.

The shell l is provided with alarge number of comparatively small openings ll situated close side by side and fitted with inserted glass bodies I2.

The glass bodies l2, when illuminated by a lamp l3, have a light lattice effect on the human eye,

that is, the post shows a dark surface which is interrupted by bright light faces uniformly distributed thereon at equal distances from one an other. With such a light lattice surface the effect on the human eye is incomparably greater than if the entire surface were illuminated uniformly by a source of light of equal total power.

Tests have shown that with the described ar- 40 rangement a suificient light effect is obtained-by a single lamp of 15- watts, whilst light posts of old construction require a candle power of the lamps of 200 wattsand more. With the new arrangement not only current is saved, but owing to the very low heat produced by the one small lamp no ventilation openings are required in the post, so that it can be hermetically sealed and any entrance of dust and moisture is absolutely prevented. The glass bodies are designed further in such a manner that they act simultaneously as reflectors, that is, reflect" any light emitted by an oncoming car or the like. The post therefore fulfills its object evenif the lamp I3 should fail to burn. This aifords the further possibility that for infrequent night traffic the lamp l3-may be switched off, without fear of the post being overrun by a car.

It will be understood that the glass inserts or reflectors l2 must embody a plurality of properties in combination, in order to be useful for a trafiic post of the construction hereinbefore described. The glass bodies must not only transmit nearly or absolutely uniformly the light issued from the lamp, but must also show an absolutely reliable reflecting effect, that is, they must reflect parallel to itself any light beam, even when coming from afar. I For this reflecting effect the reflecting action of metal foil or metal mirrors cannot be used, since such mirrors would prevent the light of the lamp l3 being transmitted. The reflection must be obtained, on the contrary, only by pure and complete total reflection.

It is further required that the outer surface of the reflecting bodies lie flush with the circumferential surface of the post shell, so that no dust or soil can deposit on the glass bodies, which would reduce the light effect. Finally, the glass bodies, must have sulficient resistance to stresses by outer pressure.

Moreover the glass bodies must have the capability of intercepting the light rays coming from an internal source of light and of condensing the light rays in some way in order to increase the light effect on the human eye.

All these conditions are met in a particularly satisfying manner by the reflecting body illustrated in Figure 3. With this body a double total reflection of the incident light beams is obtained. Every incident light beam l0, l0 meets a surface portion I; which projects the beam onto another surface portion l5 extending normally thereto. From this second surface portion IS the beam i6, i6 is reflected parallel to the direction of the incident beam l0, ID. The reflecting bodies of this construction illustrated in Figures 1 to 3 are designed as conical revolution bodies with a top angle of degrees. They are formed with an offset edge l8 by which they are inserted in the sunk edge of the apertures ll of the shell I where they are cemented. In this way their plane frontal surfaces I! lie flush with the outer surface of the shell I. The provision of the sunk edge i9 not only secures a reliable and dust-proof seating of the reflectors in the shell, but affords also a strengthening effect on the latter, so that the shell may be made of comparatively thin sheet metal.

Owing to the point of the reflecting bodies projecting comparatively far into the inner space of the post, they intercept to a particularly great extent the Iight beams emitted by the lamp l3. The uniform distribution of the light of the lamp on the reflectors may be notably improved further by the inner surface of the shell I being covered with a reflecting material, such as white enamel or the like. Furthermore, a mirror reflector may be provided opposite the lamp 13, which may be disposed on any other desired place within the post, for. example in the top portion thereof. Such a reflector gives in co-operation with the reflector 22 of the lamp l3 an absolutely uniform distribution of the light on the individual reflectors l2.

The glass forming the reflecting bodies is provided with the highest possible index of refraction in order to enable the reflection of light rays sible from that of the axis of the bodies.

Instead of conical reflectors glass prisms 23, Figure 4, may be made use of, which possess a. plane, or, if curved according to the surface of the shell, a cylindrically curved frontal surface and two back surfaces for total reflection which lie normally to one another. Such reflectors may be formed by horizontal or vertical straight or curved glass strips, but their effect is not so satisfying as that of the conical bodies shown in Figure 3.

The glass of the reflectors may be coloured according to requirement, so that the post may give any desired traific signals which are clearly visible. for more than meters.

Instead of sheet metal, the shell of the post may be made from iron or concrete. In the latter case the shell 3| must be provided with internal indentations 24, Figure 5, for the reflectors l2, due to its greater wall thickness, so that the light beams emitted by the lamp may easily meet the reflectors. These indentations 24 advantageously are made conical and a reflecting effect may be obtained by coating them with white enamel or the like.

In order to render superfluous the provision of a special foundation-see the foundation block 5 in Figure 1in the embodiment of Figure 5 the base plate 6 which is made of concrete or iron; is put onto the ground and an anchor post 26 is driven through a central aperture 25 thereof and secures the plate 6 against tilting. The lower portion 21 of the concrete shell may be fixed to the base plate 6 in a simple manner by pouring a suitable mortar material 28 into the space between the shell and the projection of .the base plate 5. When struck by a vehicle, the post then turns over from the plate 6 without being notably injured. In order to secure this, the mortar material 28 must be comparatively soft.

We claim:---

1. In a light post for traflic purposes, a shell, the inner surface of said shell being covered with a reflecting material, an internal source of light axially arranged at one end of said shell, a plurality of small perforations closely arranged side by side and distributed substantially over the,

whole area of said shell to form a light lattice work, small glass bodies inserted in said perforations, said glass bodies having portions projecting into the interior of said shell, said portions having surfaces adapted to receive and transmit light rays from said internal source of light and for totally reflecting light rays impinging thereon from an outside source of light.

2. In a light post for traffic purposes, as defined in claim 1; said perforation having sunk edges, said glass bodies having oflEset edges adapted to be seated and cemented in the sunk edges of said perforations whereby the outer surfaces of said glass bodies are positioned flush with the outer surface of said shell.

3. In a light post for traffic purposes, as defined in claim 1; said surfaces of each glass body being made normally to one another.

4. In a light post for traffic purposes, as defined in claim 1; the glass of said glass bodies having a high index of refraction.

HANNS GRUSSENDORF. ALEXANDER VARREN. 

